The prior invention related to moldable friction element compositions prepared by substitution cermet powder (D) consisted of oil coke carbon and metal Fe series for the whole or a part of inorganic binders for the friction element. But it is found that the composition has faults as follows:
(a) The above mentioned cermet powder (D) contains 20-35% of metal Fe. Thus, frictional force of the friction substance contained the cermet power (D) is reduced by oxidation of metal Fe on the surface when the cermet powder (D) is exposed to the friction surface under severe oxidating condition.
(b) The friction substance added the cermet powder (D) of the above prior art has the low coefficient of friction, e.g. about 0.29-0.30. That is, the surface the friction substance is hard solid having superior abrasion resistance but when it is rubbed on the other object, it has specific adhesive frictional action. Therefore, the frictional substance is favourable in its brake force but the smooth brake force may be often reduced by the specific frictional force and in any case, frictional noise may be occured.
(c) As a fabric binder, asbestos is added to the friction element but it is known all over the world that it should not be used in the industry since it is harmful to persons.